Continuous reactor



June 11, 1940. w. SEMON CONTINUOUS REACTOR 2 Sheets-Sheet 1 Filed June21, 1937 N NN June 11, 1940. w. SEMON CONTINUOUS REACTOR Filed June 21,1937 2 Sheets-Sheet 2 Patented June 11, 1940 v I 2,204,156

UNITED STATES PATENT OFFICE CONTINUOUS REACTOR Waldo L. Semon, SilverLake Village, Ohio, as-

signor to The B. F. Goodrich Company, New York, N. Y., a corporation ofNew York Application June 21, 1937, Serial No. 149,366 3 Claims. (01.23-290) This invention relates to a continuous reactor through theopening 4 into the reaction chamber. for producing organic chemicals.More speci- The reaction chamber is enclosed by the tube 5 fically, itrelates to an apparatus into which cor- Which I prefer to make of acorrosion-resistant rosive reactants are continuously introduced andlow-expansion glass such as the b r silioate glass 5 from which productsare continuously removed known as Pyrex. This tube is not attacheddiwithout interrupting the reaction, rectly to the outer walls of thereactor but rests As a general rule, reactions which are used to p a PDframe Consisting O the longisynthesize organic compounds requireconsideru a ba 6 and t Crossbars The D- able time, usually hours andeven days to reach porting frame s s upon the pr s -res s 1O completion.Since high temperature and presmetal tube 8 which encloses the wholeglass tube 10 sure usually shorten the time, preparations are 5. Thetube 8 is fitted at each end with the often made in autoclavesin whichthese condiheads 9 and I0, and the caps II and I2 which tions may beachieved. The charge of reactants contain the set-screws I3 to tightenthe heads is run into the cool autoclave and is then heated a ainst thas s s packing The tub 8 a s 15 at the desired temperature and pressure.When contains the inlet I5 leading from a conventional 5 the reaction isfinished, the autoclave is usually meteri p mp 5 throu h wh chnon-corrosive cooled and the pressure is released before the reactants ea d t e fitting l5 Wh c leads contents are removed. Thus, much heat islost to a p essure g u e Shown) A safety Valve by the cooling betweenthe successive runs, and i p v d, consisting f h p pe cket i theautoclave is not operating for considerable Welded to he u e n h p p Ive periods of time while it is being discharged and with a metal disc l9h l n place by the p 20 recharged. containing the holes 2| to permit therelease of Where corrosive charges are to be used, the (1113- P essu ifh disc b Most O the length ficulties are multiplied. Many commonorganic0f h u e 8 Surrounded by a heating j c e compounds are prepared fromreactants which consisting of the tube 22 welded to the sleeve 25 haveacorrosive action upon metals, hence autorings 23 Which in turn, weldedto e u claves lined with glass or other inert ceramic 8 and to the legs24. The drain for tube 22 conmaterial must be used. These liningsusually, sists of the pipe socket 5 fitte W t e p have a low rate ofheat transfer, and additional Tube2'l which opens O O tube 22 ou p pe 90time is required to bringthe charges to a reactsocket 28 acts as acondenser, and is surrounded 30 ing temperature. by the water jacket 29.

It is an important object of my invention to Referring to the pressurerelease mechanism provide a reactor which can be used continuously,shown in Fig. 2, the Pyrex g ass Coupling 30 is thereby eliminating thenecessity of periodically joi ed to e e 5 by a joint p d with asbeingemptied and refilled. Other objects are t bestos packing 3|. The otherend of the coupling provide a reactor which does not have to be isreduced to a cap y u d p s s h ou cooled to be discharged, to. provide areactor of, e pa nut 32 and uts he needle Valve small capacity whichwill producealarge amount body 33 m of po a or other nert ma- 2 of theproduct per unit time, and to provide a terial, a porcelain spark pluginsulator being very 4O corrosion-resistant lining in a reactor in whichSu e The needle Valve y is Set in the the problem of the rate of heattransfer is minipacking gland 34 Which is Screwed into e h a mized.Other objects will be apparent from the 0 a d C t s the pe ut 35 t0 orcethe following description and the drawings which asbestos packing 36tightly in place. The tapered are made a part thereof. end of the needle31 which may be made of any In the accompanying, drawings, Figs. land 2,corrosion resistant material of sufiicient metaken together, form aperspective view, partly chanical strength, such as the acid resistantbroken away and in section, of the reactor, Fig. alloy known asHastelloy, fits tightly into the 2 being on a somewhat larger scale thanFig. 1. needle valve body 33 and the other end rests in Fig. 3 issectional view taken on line 3-3 of the cup 38. The bracket 39 isattached on one Fig. 1. end to the cap l2 by the screws 40, and in the50 Referring to the drawings, the corrosion-reother end carries theadjusting screw 4| which sistanttube I of silver-lined metal, leadingfrom rests on the cup 42 holding the spring 43 against a conventionalmetering pump la, is tightly the cup 38. The glass tube 44 fits overtheouter screwed into the nipple 2 and abuts the glass endof the needlevalve body 33, and is supported tube 3 which leads the corrosivematerials on the other end by the hanger 45 attached to the bracket 39and containing the rubber bushing 46 which fits over the glass tube. Theproducts are continuously discharged into the glass gube M and leave thereactor through the outlet To illustrate the operation of the reactor, Iwill show in some detail the preparation of meso, meso, dimethylacridane from acetone and diphenylamine in the presence of aconcentrated hydrochloric acid catalyst. -To make meso, meso, dir'nethylacridane, the reactants are preferably heated at 259 C. under a pressurelbs. per sq. in. for two hours. weight of diphenylamine are heated with1 part of acetone until the diphenylamine is entirely in solution. Thesolution is then continuously pumped into the reactor through inlet 15at such a rate that it takes two hours to pass fromthe entrance :2 ofthe glass tube 5 to the needle valve 33. In operation, the solutionflows through the annular space between tubes 5 and B to the other endof the reactor, where it enters the glass tube through opening. 4. Theconcentrated hydrochloric acid is continuously pumped through the glasstube 3 silver-lined tube i at such a rate that the volume of acidisone-tenth that of the other. reagents, and enters the reaction chamberthrough the The tube 22 is partially filled with diphenyl oxide, whichboils at 259, through the condenser tube 21, and is heated by gasburners (not shown) or other heating means underneath the reactor untilthe diphenyl oxide just boils. The mixture of acetone and. diphenylaminebecome heated to 259 C. as they pass through tube 8 from inlet I5 to theentrance 4 of thereaction tube 5. When the hydrochloric acid is added,therefore, the reaction begins immediately. The reaction mixture passesthrough tube 5, taking two hours to go from entrance 4 to the needlevalve 33. The pressure at which the valve will release the productsisvaried by screw 4 I which is adjusted to release at a pressure of 600lbs. per sq. in. for this particular reaction. Thus, there is a steadyflow of products from the outlet 41, which, besides unreacteddiphenylamine con sists chiefly of meso, meso, dimethyl acridane.

The rate at which the desired products are prepared depends only on thevolume of the reaction chamber reagents are forced through the reactor.The reactor can readily be made up in any desired size to produce thedesired quantity of products, of if desired, different reaction chambers5 of different volumes may be inserted in the shell 8, depending on theparticular products which. are

to be prepared.

Many compounds. other than meso, meso, dimethyl-acridane may be made inthis reactor. The presence of solids and gases interferes with theoperation of the pressure release valve, hence any solids or gases whichare added or formed should be maintained in solution by suitabletemperatures and pressures or by the addition of solvents. least oneconstituent of which is non-corrosive to metal, may be handled in thisreactor. The non-corrosive constituent is introduced into the metalshell 8 and becomes heated by contact with the reaction chamber 5 andfinally by the heating jacket, and is at full reaction temperaturebefore it enters the reaction chamber and encounters the otherconstituent. The corrosive constituent, which is preferably so chosen asto constitute only a minor portion of the total volume of the. reactionmixture, is introduced diof 600- 11.5 parts by 5 and the rate at whichthe In general any reaction mixture, at

portion of the pressure-resistant metal shell.

The product issuing from the reaction has given up a large portion ofits heat to the inflowing non-corrosive reagent and therefore requiresless cooling than would otherwise be necessary.

As a further example, diphenylamine may be prepared by introducing 64volumes of aniline as the non-corrosive reactant and 108 volumes of amixture consisting of aniline 46.5 parts, aniline hydrochloride 64.3parts and water 8 parts as the corrosive reactant. This corrosivereactant can be prepared by mixing together aniline 2 mols andhydrochloric acid 1 mol in a glass-lined kettle and distilling until thetemperature of the liquid reaches 133 C. Aniline lost during thisdistillation should be replaced. The reaction by which diphenylamine isformed requires 3 hours at302 to 310 C. at a pressure of 700 lbs. persqin. The charge issuing from the reactor consists of diphenylamine,aniline and ammonium chloride. It is neutralized with ammonia, the

oily layer separated and distilled. The conver sion to diphenylamine isabout 40% and. the yield based upon unrecovered aniline is 96%.

In a like manner di-p-tolylamine may be made from p-toluidine,p-toluidine hydrochloride and Water.

Thereaction chamber may be made of any desired corrosion-resistantmaterial no matter how fragile, how different in thermal expansion fromthe metallic shell, or otherwise unsuitable for the manufacture ofpressure equipment, for it is not exposed to. any differential pressureor other mechanical strain. The only portions of the entire reactorwhich are exposed both to corrosion and mechanical strain are the tubethrough which the corrosion resistant constituent is introduced, and theneedle valve 33 and needle 31, but these form such a small part of theapparatus that they can inexpensively be made of noble .metals,corrosive-resistant alloys, or the like; The major part of the reactoris ordinarily made up of mild or medium steel pipe of a size sufficienttoresist the temperature and pressure encounteredand is therefore farcheaper than the specially constructed autoclaves or reactors madeentirely of corrosion-resistant materials which have heretofore beenemployed for reactions of this type.

It is plain that this reactor, although most advantageous for carryingout pressure reactions of corrosivematerials, may also be employed forreactions at atmospheric pressure by simply omitting or removing theneedle 31 or the entire needle valve, or even for reacting non-corrosivematerials.

Although it has been stated above that the reagents are introducedcontinuously, it will be understood that the introduction need not beabsolutely continuous, but may consist in the injection of a successionof closely recurrent increments such as are produced by the positivedisplacement piston pumps ordinarily used for the 7 ceeding the spiritand scope of my invention as defined in the appended claims.

I claim:

1. A reactor for the continuous reaction of reagents one of which iscorrosive, comprising a shell, a corrosion-resistant reaction chamberwithin the shell, the shell being made of a structurally strong materialdifferent from that of the reaction chamber, the reaction chamber havingat one end an outlet extending through the Wall of the shell and at theother end an opening through which the contents of the shell may enterthe reaction chamber, a corrosion-resistant inlet for the corrosivereagent extending through the wall of the shell and through the saidopen ing and debouching within the reaction chamber, and an inlet intothe shell for the other reagent.

2. A reactor as in claim 1 in which the inlet for the other reagent isat the end of the shell adjacent the outlet so that the reagent betweenthe wall of the shell and the reaction chamber flows 3 countercurrent tothe reaction mixture Within the reaction chamber.

3. A reactor for the continuous reaction of reagents one of which iscorrosive, comprising a shell, a corrosion-resistant reaction chamberwithin the shell, the shell being made of a structurally strong materialdifferent from that of the reaction chamber, the-reaction chamber havingat one end an outlet extending through the wall of the shell and at theother end a relatively restricted opening through which the contents ofthe shell may enter the reaction chamber, a corrosion-resistant inletextending through the wall of the shell and through the said opening anddebouching within the reaction chamber near the open end, means forcontinuously feeding the corrosive reagent through the said inlet, aninlet into the end of the shell adjacent the outlet of the reactionchamber and means for continuously feeding the other reagent through thelast-mentioned inlet.

WALDO L. SEMON.

